Why do some streets do a dogleg?

Back in West Texas, a friend of mine bought a new house in a new section of town. In the older parts, the streets were all straight and gridlike, but in newer parts like this one they were curvy. My friend told me the government had banned government-backed home loans for houses on straight streets, because of the accident rate from speeding cars hitting children, so he had to buy a house here in order to get a loan,plus that’s why all the new streets were curvy.

However, this particular person was always chock-full of incorrect information, so I don’t know how true that is.

That’s not how things work with city “additions” of the last 150 years or so. The house lots, the alleys, and the area dedicated as a public road are all determined when the plat is recorded in the county courthouse.

The date of the houses isn’t important. What’s important is the date of the subdivisions, and I feel confident you’ll find that the Springfield Manor subdivision (west of 31st) was done at a different time than the Parkdale subdivision east of there. Parkdale seems to have been laid out with alleys while Springfield Manor wasn’t. One may date from 1915 and the other from 1938.

Another factor I see in looking at a topo map is the presence of a hillside on the north side of Lafayette east of 31st. That might mean that keeping it on the same alignment it has west of 31st would require thousands of dollars in grading costs for the subdivider or the homebuilder.

Well, that has the germ of truth in it. When the Federal Housing Administration was established in 1934 to guarantee mortgages, homebuilders saw it as devoted to ensuring the success of their projects rather than as governmental interference, so were much more receptive to FHA’s underwriting criteria than to local subdivision regulations with similar aims. FHA’s 1935 technical standards suggested that streets should fit the local topography and have widths suited to their requirements (not overbuilt on the assumption that every lot might someday contain a factory or apartment house). But FHA never denied a loan because a house was built on a straight street.

If you ever get really bored, fire up something like eagle or kcad (or any other pcb design software) and doodle in a map of your neighborhood. Then see what auto-routing does to it.

Too geeky?

My city is laid out with a mixture of river-parrallel, “true NS” and “magnetic NS”, then with the subdivisions, swamps, mountains, river fords and gullies infilled on that.

Where I live the country roads jog when two townships meet .

The Public Land Survey System generally prescribed “correction lines” every 24 miles as you proceeded north to account for the curved-earth thing. But the surveyors were lowest bidders, subject to human frailty, and often working in impenetrable swamp, dark forest, or steep hillsides, so the survey work was full of imperfections. More importantly, they thought they were evenly dividing land for sale, not laying out future roads. The survey often came 40 years before anyone thought of section-line roads. The Master has twice written about this, though the link seems to be dead.

The various imperfections that made the farmland holdings equal in acreage, however, rippled down to the present day, as the farm fields and pastures of 1880 became the subdivisions of 1920. Often each developer laid out the streets on his 40 acres evenly, and the next guy over did the same thing, leading to jogs of 20-100 feet where they met. Before the automobile, at walking speeds, this was of little practical consequence. Here’s a series of maps showing the process and the resulting urban street pattern.

Yep. While you can lay a string on a globe in a straight line, you can’t flatten out a square without some adjustment.

A section is one square mile (or they try to be) a township is 6x6 sections. These adjustments typically occur at the boundaries of adjoining townships.